The invention concerns a locking device for, with a lock, locking an already closed door which is mounted with hinges on a frame in a wall and is held in closed position by a turnable locking bar which, at least at one end, has a projection for, by rotating the bar, engaging with a holder on the frame.
Trucks with closed compartments and containers are normally provided with a double wing door which is placed in one of the end walls in order to facilitate loading and unloading. The doors are swingably hinged on a frame in the end wall, and at least one of the doors is held in closed position by a locking bar which is rotatably journaled in a number of brackets on the door and having a handle for rotating a projection at each end of the bar into engagement with corresponding holders on the frame. In this position, the handle can be locked to a lock fitting on the door with e.g. a padlock to secure against theft. However, in many cases, the container is merely sealed with a seal which is broken and subsequently replaced with a new seal at e.g. customs checks.
However, the doors of this known structure can relatively easily and quickly be broken open by e.g. sawing through the handle or breaking this and the lock fittings to pieces. Another disadvantage is the fact that the lock requires keys which must be brought along or be at the customs station and at the recipient. This is a considerable problem considering the very large number of e.g. containers that are today circulating all over the world, and which in fact require the presence of a corresponding number of keys and a complicated system for storing and keeping the keys in order.
The object of the invention is to show a locking device of the kind mentioned in the opening paragraph that provides a better guarantee against burglary than known so far.
Another object of the invention is to show a locking device of the kind mentioned in the opening paragraph that can function independently of keys.
The novel and unique features according to the invention are the fact that the locking device comprises a lock hole running through the locking bar, the lock hole assumes, in the closed position, a direction mainly parallel to the door plane, a house with a channel attached on the door, the channel encloses the locking bar, and a bolt guide which is in alignment with the lock hole in the closed position; and a sliding bolt for sliding through the bolt guide and the lock hole and locking the locking device by means of locking means which engage with tumblers in the lock. Thereby, an effective, burglary-proof construction is obtained in a simple manner.
Owing to consideration of space and strength the house can have an opening on one side of the channel for taking up the lock whereas the bolt guide is made on the other side so that the bolt is supported on both sides of the lock hole.
The bolt can furthermore have a head for preventing lock and bolt from being pulled out of the house in locked condition.
In a simple, inexpensive embodiment, one of the brackets of the locking bar can be used as house. On each side of the channel enclosing the locking bar, the bracket is provided with a sleeve for taking up the lock and a bush, respectively, containing the bolt guide.
By placing the bracket immediately against the holder of the frame for, by rotating the locking bar, retaining the projection of this bar, the advantage is obtained in that it is only possible for any unauthorised person to saw over or cut the locking bar above the bracket. However, the rest of the bar is still engaged with the locking device which thereby still locks the door securely.
In an especially advantageous embodiment, the lock can be a combination lock whereby the previous need for having a large number of keys is eliminated. The code can quickly and easily be communicated by e.g. telephone, and the combination lock can quickly be replaced or recoded if necessary.
The combination lock can have annular tumblers with radially inwards turned tumbler keys, and the locking means of the bolt can at the same time be made of a number of encircling grooves for taking up the tumbler keys in locked condition, a longitudinal free mortise for taking up the tumbler keys in unlocked condition, and a pawl placed in the house and engaging with the free mortise for controlling the angular position of the bolt in relation to the lock.
Even if a door is already locked by a lock, it still is often demanded that it is sealed with a seal which is broken and then replaced with a new seal at e.g. customs checks.
In one variant of the locking device according to the invention, the sliding bolt can advantageously be made as a seal. In that case, the free mortise then ends blindly in the bolt, and the pawl engages with the slot at a distance from the free end of the bolt. When the lock is unlocked, the bolt is then pushed off in the direction opposite of the lock by a prestressed compression spring in the house until the pawl hits the end of the mortise and the head projects from the house. In this position, the customs service can now e.g. cut or saw over the head which then can be pulled free of the lock hole of the locking bar by pulling on the lock so that the door can be opened.
The head of the bolt is easiest to remove when there is an encircling groove under the head. The groove must be so deep that the head can easily be knocked or broken off.
A second variant according to the invention can be made for the use of a conventional seal. In that case, the house has a sealing hole extending transversely to the bolt guide and serving for mounting of the seal. In this case, the free mortise can end at the terminal surface of the bolt so that the bolt can be pulled free of the lock hole when the seal is broken and the lock can be unlocked.